Portable computer unit have become smaller and lighter, they have become easier to conceal. Such ease of portability and concealment has also increased risk of their theft, and hence protecting such units from unauthorized relocation has become increasingly paramount. To mitigate unauthorized relocation of such portable computing units, various forms of protections such as a “security device” or “merchandise display device,” are developed. Such arrangements permit a potential purchaser to examine and operate the demonstration model, without increasing a likelihood that the display product will be stolen or removed. For example, various locking systems and arrangements have been provided, wherein lock structures have been designed to supply a mechanical grip on holes that are devised within sides of the computing units.